= Band ratio image
{title2=$L_1/L_2$}
An image formed by dividing corresponding calibrated pixels in two spectral bands. If their signals have a common multiplicative factor, $L_1=k\rho_1$ and $L_2=k\rho_2$, their ratio is $\rho_1/\rho_2$ and does not depend on $k$. This explains suppression of some common illumination effects and enhancement of spectral contrasts. Additive atmospheric radiance and small denominators prevent exact cancellation and can amplify errors. <Normalized difference vegetation index> is a related normalized spectral contrast.
Back to article page
